In the particular case of a cellular radiotelephone, energy consumption is of the pulse type, i.e. it varies over time with peaks during short time intervals, the time intervals where consumption is high typically occurring while the radiotelephone is transmitting.
Conventional electrical power supply circuits for powering portable appliances are available on the market with different capacities and with a variety of electrochemical cells. In this kind of appliance, it is always desirable for the power supply circuit to be as light and as compact as possible while also providing electricity for as long as possible. In other words there is a continuing search for power supply circuits having the best possible energy efficiency.
In addition, since portable appliances of the cellular radiotelephone kind are sensitive to electromagnetic interference, it is desirable for such appliances to have power supply circuits that emit little or no noise interference.